I subscribe to the comment feed for a WordPress blog, ekonomistas.se, using Google Reader. Since several months maybe half of the comments are not showing up in Google Reader. Furthermore, (almost) always the comments that actually show up, show up in batches of ten. Why? No other blogs I read using Google Reader (more than 50, but I think none of them are WordPress) show this behaviour,
I also subscribe to the main feed for the same blog and it works as expected.